Spring tension grinding machine



July 1, 1952 A. R. JOHNSON 24,601,749

SPRING TENSION GRINDING MACHINE July 1, 1952 A. R. JOHNSON SPRING TENSION GRINDING MACHINE 6 Sheets-Sheet 2 Filed Aug. 15, 1949 INVENTOR. )4r/z @Za/c/o/zso/e,

ATTORNEYS July 1, 1952 A. R. JOHNSON SPRING TENSION GRINDING MACHINE S Sheets-Shea?. 3

Filed Aug. l5, 1949 6 Sheets-Sheet 4 A. R. JOHNSON SPRING TENSION GRINDING MACHINE July 1, 1952 Filed Aug. l5, 1949 ""lu qu 1 July 1, 1952 A. R. .JOHNSON 2,601,749

SPRING TENSION GRINDING MACHINE Filed Aug. l5, 1949 6 Sheets-Sheet 5 @gaf/2.

IN VEN TOR.

July 1, 1952 A. R. JOHNSON SPRING TENSION GRINDING MACHINE 6 Sheets-Shee 6 Filed Aug. l5, 1949 WJNU INVENTOR. f/ZalZ?. /0/z sag AQNI NST

Patented July 1, 1952 UNITED STATES PATENT OFFICE This invention relates to a sharpening machine, and more particularly to a machine for sharpening knives and similar edged implements.

The object of the invention is to` provide a sharpening machine which includes rotary sharpening or grinding elements that can be adjusted for work of different sizes or shapes.

Another object of the invention is to provide a sharpening machine which is power operated, the machine including grinding elements that are adapted to form a throat therebetween for receiving a knife or other implement to be sharpened and wherein the knife is engaged by the grinding elements.

Still another object of the invention is to provide a sharpening machine for resharpening the cutting edges of knives and the like, the machine including grinding elements whose parts can be positioned as desired, there being a resilient means for maintaining the parts of the grinding elements under proper tension.

Still another object of the inventionis to provide an implement-sharpening machine which is constructed so that the sensitive moving parts thereof are protected from contamination, the machine being adapted to be used for domestic or commercial purposes, and wherein the sharpening is accomplished by endless abrasive belts, engaging the cutting edge of the implement to produce a smooth, sharp cutting edge on the implement.

Still another object of the invention is to provide a sharpening machine whose parts can be readily removed and replaced as desired, the machine being simple and inexpensive to manufacture. i

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure 1 is a vertical sectional View through the implement-sharpening machine, according to the present invention;

Figure 2 is a sectional View taken 2-2 of Figure 1;

Figure 3 is a sectional View taken on the line 3-3 of Figure 1;

Figure 4 is an enlarged sectional view taken on the line 4-4 of Figure 3;

Figure 5 is an enlarged sectional view taken on the line 5--5 of Figure 1;

Figure 6 is an enlarged sectional` view taken on the line 6-6 of Figure 1; l

Figure 7 is a vertical sectional View showing a modified form of the sharpening machine;

Figure '7a is a sectional view taken on the line 'lala of Figure 7;

Figure 8 is a sectional View taken on the line 8-8 of Figure 7;

Figure 8a is a fragmentary side elevational view, with parts in section, howing another modified arrangement of the sharpening elements;

Figure 9 is a vertical sectional view through still another modified form of the sharpening machine;

Figure 10 is a sectional view taken on the line lll-I0 of Figure 9;

Figure 11 is a sectional view taken on the line Il*l| of Figure 9;

Figure 12 is a vertical sectional view through another modified form of the invention;

Figure 13 is a sectional view taken on the line |3-l3 of Figure 12;

Figure 14 is a sectional view taken on the line M-Ill of Figure 12.

Referring in detail to Figures 1 through 6 of the drawings, there is shown a machine for sharpening knives or other similar edged implements. The sharpening machineof Figures 1 through 6 includes a hollow housing 20 which may be fabricated of any suitable material, and the housing 20 includes a bottom wall 2l and a pair of spaced parallel end walls 22 and 23. Extending between the end walls 22 and 23 is a pair of spaced parallel side walls 24 and 25', Figure 3. .A cover 25 is adapted to close the upper open end of the housing 20, and the cover 25 is detachably connected to the housing 20 by suitable securing elements, such as screws 26. The cover 25 is provided with an opening 2l therein for a purpose to be later described.

Positioned in the housing 20 and supported on` the bottom wall 2| is a power source, such as an electric motor 28, which is adapted to be connected to a suitable source of electrical energy by means of a cable 29. The motor 28 serves to rotate the drive shaft 30, the shaft 3U having one of its ends rotatably supported in a bearing 3| which is part of the plate 32, Figure l. The shaft 30 is provided with a keyway 33, and mounted on the shaft 3B is a pair of spaced bevel gears 34 and 35. A key or screw 36 projectsthrough each 0f the bevel gears 34 and 35 and into the keyway 33, so that rotation of the shaft 30 causes rotation of the bevel gears 34` and 35. A coil spring 3l is circumposed on the drive shaft 30 and the coil spring 3l is interposed between the bevel gears acolfrse 34 and 35 for normally urging the bevel gears to their proper spaced relation.

Arranged in the housing and secured to the walls thereof is a body member 35 which supports a pair of grinding or sharpening elements 39 and 4U. The grinding elements 39 and 4D are similar in construction, and these grinding elements coact to denne a V-shaped throat 4l therebetween for the reception therein of the implement, such as a knife, to be sharpened. Arranged below the throat il and secured to the body member 38 is a bumper member l2 which may be of any suitable material, such as rubber, and the bumper member 42 prevents the knife or other implement from striking the body member 38 so that damage to the implement will be prevented.

The grinding element 59 includes a pair of tapered pulleys 43 and 44 which are mounted for adjustable movement toward and away from each other. The other grinding element 4i] includes a pair of similarly-tapered pulleys 45 and 35. Trained over the pulleys 43 and .14 is an endless abrasive belt ll'l, while trained over the other pair of pulleys 45 and l5 is an abrasive belt f'. As shown in Figure 4, the tapered pulleys i3 through 4.5 are preferably provided with grooves lg for receiving therein ridges 5l that` project inwardly from the belt 45, the ridges 5l and grooves i5 coacting to prevent accidental dislodgment of the abrasive 'belts from the tapered pulleys. The abrasive belts are provided with a layer of suitable abrasive material 55, Figure 4, on their exterior surface. Further, each of the tapered pulleys is provided with an annular flange 52 on their lower ends, and the flanges 52 help to insure that the abrasive belts be properly positioned on the pulleys.

The pulley 4s is supported by an L-shaped bolt 53 which projects through a slot 55 in the body member 33. An end of the bolt 55 is threaded eXteriorly, as at 55, for a portion of its length, and a suitable nut 55 is arranged in threaded engagement with the portion 55. The bolt 53 has a portion thereon slidably projecting through a bushing 51 which is part of the plate 52, and the coil spring 53 is circumposed on the bushing 5l, the coil spring 58 abutting the washer 55, Figure 1. The washer 59 is secured to the bolt 53, and the adjacent end of the spring 53 is secured in any suitable manner to the washer 59. The coil spring 58 is of such a construction that it normally draws or urges the pulley 44 toward the end wall 22 so that the belt 4l will be maintained under proper tension. Further, by adjusting the nut 55, the tension on the coil spring 58 can be adjusted as desired, The other corresponding pulley 4:5 on the grinding element 40 serves the same purpose as the pulley 44, and the construction and adjustment thereof is the same as the previouslydescribed construction of the pulley 44. Thus, an L-shaped bolt 55 rotatably supports pulley llt, and an adjusting nut 5l is arranged in threaded engagement with the end of the bolt 55, the nut 5l serving the same purpose as the nut 55.

Arranged at right angles with respect to the drive shaft 35 is a driven shaft 52 whichhas its upper end connected to the pulley 43. The lower end of the driven shaft 52 carries a bevel gear 53 which meshes with the bevel gear 34 on the shaft Sil. The shaft 62 projects through a slot 5,4 in the body member 38, and a sleeve 65 rotatably embraces the shaft 62. Arranged in spaced parallel relation with respect to the driven shaft 52 is a driven shaft 65 which has its upper end connected to the pulley 45. The shaft 66 projects through a slot 61 in the body member 38 and carried by the lower end of the driven shaft 66 is a bevel gear 69 which meshes with the bevel gear 35. A sleeve 'I0 slidably embraces the driven shaft 55.

A means is provided for moving the driven Y shafts 52 and 55 toward and away from each other, whereby the size of the throat 4l can be adjusted to accommodate knives or other implements of varying sizes or shapes. A rod Il has one end secured to the sleeve 65, and the other end of the rod il projects out of the end wall 22, Figure l. A manually-operable operating lever l2 is pivotally connected to the projecting end of the rod 'Il by means of a pin T3. Thus, the lever 'l2 can be shifted from the position shown in Figure l. to a position in alignment with the rod il so that this movement of the lever 'l2 will cause longitudinal shifting movement of the rod ll, whereupon movement of the pulley 43 will be effected. The rod il is provided with a splined portion 'lf3 which projects through a bushing 'l5 that is part of the plate 32, Figure 6. A coil spring 'l5 is circumposed on bushing '15, and the coil spring 'l5 is interposed between the plate 32 and a collar ll which is secured to the rod 1I. The coil spring 'le normally urges the driven shaft 52 away from the end wall 22. Similarly, a means is provided for adjusting the position of the pulley 55 of the grinding element 4t. Thus, an operating lever 18 functions in the same manner as the lever l2, and the operating lever 18 is pivotally connected to a rod 'I9 which is secured to the sleeve lil. Thus, by proper pivotal movement of the lever i3, the pulley 45 can be moved relative to the pulley 43, whereupon the size of the throat 4I can be adjusted as desired to accommodate various sizes of implements which are to be sharpened.

In use, the implements, such as the knife, to be sharpened, are passed through the opening 2l in the cover 25 and the knife is arranged in engagement with the abrasive belts 41 and 48. Thus, the knife is positioned in the throat 4| which is shaped like a V. Then, upon actuation of the motor 28, the shaft 50 will be rotated to thereby drive the shafts 52 and 65, which results in the endless abrasive belts 41 and 48 being revolved, whereupon a sharp beveled edge will be produced on the knife. The pulleys 44 and 45 are constantly maintaining the belts of the grinding elements under proper tension, due to the previously-described structure. Further, the size of the throat 4l can be adjusted by proper positioning of the levers 12 and 18. j

Referring in detail to Figures 7 through 8 of the drawings, there is shown a modified sharpening machine which is adapted to grind only one side of a knife or implement at a time. The sharpening machine of Figures 7 through 8 includes a hollow housing Sl) which has a cover 3| detachably connected thereto, the cover 8l being provided with a recess B2, whereby the implement can be positioned in the throat when the implement is to be sharpened. Arranged in the housing is an electric motor 83 which is reversible, whereby it can be made to rotate the drive shaft 34 in opposite directions, as desired, The drive shaft 84 is rotatably supported by a bearing bracket 85, Figure '7, and the motor 83 is adapted to be connected to a suitable source of electrical energy.

Arranged above the motor 83 is a grinding element 86 which includes a pair of tapered pulleys 81 and 88, there being an endless abrasive belt 89 trained over the pulleys 81 and 88. The pulley 81 is supported on an L-shaped bolt 99 which projects through a slot 92 in a body member 93, and a coil spring 9| is circumposed on the bolt 99 for maintaining the belt 89 under proper tension. A nut 94 is threaded onto the bolt 99 and the nut 94 serves the same purpose as the previously-described nut 56. The other pulley 88 of the grinding element 86 is connected to the upper end of a driven shaft 94, the driven shaft 94 projecting through a slot 95 in the body member 93.

Secured to the lower end of the driven shaft 94 is a bevel gear 98 which meshes with a bevel gear 91 that is keyed to the drive shaft 84, there being a coil spring 99 for normally urging the bevel gear 91 into engagement with the bevel gear 96.

For moving the tapered pulley 88, an operating lever 99 is provided, and the lever 99 functions in the same manner as the previously-described levers 12 or 18, A coil spring |99 normally urges the lililley 88 toward the end wall |9| of the housing A tapered guide Wheel |92 coacts with the grinding element 89 to dene a V-shaped throat |93, the guide wheel |92 being supported on a U-bolt |94. A pair of coil springs |95 are circumposed on the legs of the U-bolt |94 for normally urging the guide wheel |02 away from the end wall |9l. A plate |96 is connected to the projecting ends of the U-bolt |94 and a thumb screw |91 is arranged in threaded engagement with the plate |95, the thumb screw |01 abutting the exterior surface of the end Wall |9|. By proper r0- tation of the thumb screw |91, the position of the guide wheel |92 relative to the pulley 88 can be adjusted as desired.

Thus, it will be seen that the sharpening machine of Figures 7 through 8 is especially suitable for sharpening butcher knives or other similar implements used for domestic purposes. The implement to be sharpened is positioned in the throat |93, and the motor 83 is actuated to cause the endless belt 89 to revolve. As the endless belt 89 revolves, it sharpens the `cutting edge on the implement, and after one side of the implement has been sharpened, the reverse side of the implement is arranged in engagement with the abrasive belt 89.

Referring to Figure 8c, there is shown another modified assembly which includes a grinding element |99 that coacts with the tapered guide wheel 92 to dene a V-shaped throat |98 for receiving therein the implement to be sharpened. The grindingV element |99 differs from the grinding element 88 of Figure '1 in that the grinding element |99 is provided with a pulley |9 which has straight sides rather than tapered sides.

Referring to Figures 9, 19 and 11, there is shown another modified form of the sharpening machine. Thus, in Figures 9 through 11 the sharpening machine of Figures 9 through 11 includes a hollow housing having a cover ||2 detachably connected thereto, there being a motor ||3 supported in the housing Connected to the motor I3 is a drive shaft ||4 and arranged adjacent the top of the housing is va pair of grinding elements ||5 and IIS. The grinding elements ||5 and ||8 coact to define a V-shaped throat |1 therebetween for the reception of the implement to be sharpened.

The grinding element |5 has a driven shaft ||9 connected thereto, while the other grinding element ||9 has a driven shaft ||9 connected thereto. Mounted on the driven shaft ||9, Fig

ure 9, is a pulley |29, and arranged in alignment with the pulley |29 is a pulley |2| which is mounted on the drive shaft ||4. A belt |22 is trained over the pulleys |29 and |2| so that rotation of the motor ||3 causes the abrasive belt of the grinding element I8 to revolve.

Mounted on the driven shaft ||9 is a gear |23 which is arranged in meshing engagement with a gear |24, the gear |24 being mounted on the driven shaft ||8. Thus, rotation of the driven shaft ||9 causes the driven shaft ||8 to rotate so that the grinding element ||5 is simultaneously actuated. The driven shaft ||9 is rotatably supported by a bearing bracket |25 secured to the housing I.

The coil springs |29 and |26', Figure 9, again serve to maintain the abrasive belt of the grinding elements 5 and ||6 under proper tension.

A means is provided for normally urging the gear |24 into engagement with the gear |23. Thus, arranged in rotatable embracing relation with respect to the driven shaft ||8 is a sleeve |21 and secured to the sleeve |21 is a rod |28. A portion of the rod |28 is slidably arranged in a bearing block |29 and the block |29 is secured to a bracket |39 which is secured to the housing ||9 so that the gears |24 and |23 remain in mesh.

The machine of Figures 9 through ll operates as follows: The motor ||3 operates the drive shaft ||4 which in turn rotates the driven shaft ||9 through the belt |22. This causes the abrasive belt of the grinding element ||9 to revolve. Also, since the gears |24 and |23 are arranged in meshing engagement, the driven shaft ||8 is rotated to thereby cause the abrasive belt of the grinding element ||5 to be revolved so that the implement positioned in the throat |1 will be sharpened.

Referring to Figures 12, 13 and 14, there is shown another modified arrangement of the grinding machine. The machine of Figures 12 through 14 includes a hollow housing |33 which has a plurality of suction cups |34 depending therefrom, whereby the machine will be kept immobile during use thereof. The sharpening machine of Figures 12 through 14 includes a pair of grinding elements |35 and |39 which coact to define a V-shaped throat |31 for receiving therein the implement to be sharpened.

Supported on the bottom of the housing |33 is a motor |39 which operates a drive shaft |39, there being a pulley |49 mounted on the drive shaft |39. Arranged adjacent the rear wall |4| of the housing |33 is a pair of stub shafts |42 and |43. A pulley |44 is mounted on the shaft |42, while a similar pulley |45 is mounted on the shaft |43. A V-belt |46 is trained over the pulley |49 and over the pair of pulleys |44 and |45.

Connected to the grinding element |35 is a driven shaft |41, while connected to the other grinding element |39 is a similar driven shaft |48, the shafts |41 and |48 `being arranged for- Wardly of the shafts |42 and |43. Mounted on the shaft |42 is a pulley |49, while a similar pulley |59 is mounted on the other shaft |43. Mounted on the driven shaft |41 is a pulley |5|, while mounted on the driven shaft |48 is a pulley |52. An endless belt |53 is trained over the pulleys |49 and |5I, there being a belt |54 trained over threaded engagement with the bolt |55.

7 the pulley |50 and the pulley |52. The `belt |54 is twisted, as best seen in Figure 13.

Thus, it will be seen that actuation of the motor |38 rotates the shaft |39 to thereby drive the stub shafts |42 and |43. Then, rotation of the shafts |92 and |43 causes the driven shafts |41 and |58 to rotate, and rotation of the shafts |411 and |48 causes the-abrasive belt of the grinding elements |35 and |36 to revolve, whereupon the implement positioned in the throat |31 will be sharpened.

rThe grinding element |35 includes a pulley |55 which is mounted on an L-shaped bar or bolt |58, there being a wing nut |51 arranged in A coil spring |53 is circumposed on the bolt |55, and the coil spring |58 normally urges the pulley |55 toward the end wall |53 of the housing |33, so that the endless abrasive belt of the grinding element |35 will be maintained under proper tension. Similarly, a spring |53 functions to maintain the abrasive belt of the grinding element 35 under proper tension at all times. By proper rotation of the wing nut |51, the tension on the coil spring |58 can be adjusted as desired.

For normally urging the driven shafts |41 and |118 toward each other, a support member |60 has one of its ends operatively connected to the driven shaft |41. An elongated bolt |8| projects through the end wall |59 of the housing |33 and is connected to the support member |60. Circumposed on the bolt |6| is a coil spring |62 which normally urges the driven shaft |41 aWay from the wall |49. Similarly, a coil spring |62' is circumposed on an elongated bolt ISI', and the coil spring |32' normally urges the driven shaft |48 away from the end Wall |83 of the housing |38. By proper rotation of the bolts |6| and Il, the tension on the coil springs |52 and |82' can be adjusted as desired.

From the foregoing, it is apparent that a sharpening machine has been provided which will elficiently sharpen implements, such as knives and the like. The sharpening machine includes grinding elements which are provided with endless abrasive belts whereby the implements will be sharpened without causing damage to the implements. The various springs on the machine keep the parts of the grinding elements under proper tension, and the sharpening machine is adapted to be used for commercial or domestic purposes. The abrasive belts on the grinding elements coact to define a V-shaped throat therebetween for receiving the implement to be sharpened. The machine is safe and emcient in operation. By using the machine of the present invention, a fine `housing and connected to Vsaid motor, a pair of Vcutting edge is produced on the implement. Both sides of the implement will be ground even, and the implement will not burn by using'abrasive belts as disclosed in the present invention. Further, the various parts of the machine can be readily disassembled for replacement as desired.

I claim: Y

1. In an implement-grinding machine, a hollow housing, an electric motor positioned in said housing, a drive shaft rotatably supported in said bevel gears keyed to said shaft and spaced from each other, a pair'of spaced driven shafts aitranged at right angles with respect to said'drive shaft, a gear mounted on an end of each of said driven shafts and arranged in engagement with said bevel gears, a coil spring circumposed on said drive shaft for maintaining said bevel gears in engagement with the gears on said driven shafts, a pair of grinding elements arranged in said housing and coacting to define a V-shaped throat therebetween for receiving the implement to be sharpened, each o f said grinding elements comprising a pair of tapered pulleys, an endless abrasive belt trained over said pulleys, one of said pulleys being connected to a said respective driven shaft, an I -shaped rod connected to the other of said pulleys and projecting through said housing, and a spring circumposed on said L-shaped rod for maintaining said belts luider proper tens1on.

2. The apparatus as described in claim 1, and further-including manually operable means for varying the size of said throat.

ARNOLD R. JOHNSON.

REFERENCES CTED The following references are of record in the le of this patent: i

UNITED STATES PATENTS 

